#ifndef __PROGTEST__
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <assert.h>
#endif /* __PROGTEST__ */

int prestuprok(int y)
{
    if((y%4==0&&y%100!=0)||(y%400==0&&y%4000!=0))
        return 1;
    else
        return 0;
}

int DenvTydnu(int den, int mesic, int rok, int d1, int m1, int y1)
{
    den = d1;
    mesic = m1;
    rok = y1;
    int a = ( 14 - mesic ) / 12;
    int y = rok - a;
    int m = mesic + 12 * a - 2;
    return (( 7000 + ( den + y + y / 4 - y/100 + y / 400 + ( 31 * m ) / 12 )) + 1 ) % 7;
}
int CountFriday13 ( int y1, int m1, int d1,int y2, int m2, int d2, long long int * cnt ) {
    int c=(y2-y1-1)/28000;
    int i,j;
    int den=6;
    int mesicDny[]={31,28,31,30,31,30,31,31,30,31,30,31};
    int mesicDnyPrestupRok[]={31,29,31,30,31,30,31,31,30,31,30,31};

    if(y1>y2||y1<1900||(y1==y2&&m1>m2)||(y1==y2&&m1==m2&&d1>d2)||m1>12||m1<1||m2<1||m2>12||d1<1||d2<1)
        return 0;
    if(prestuprok(y1)){
        if(mesicDnyPrestupRok[m1-1]<d1)
            return 0;
    }
    else if(!prestuprok(y1)){
        if(mesicDny[m1-1]<d1)
            return 0;
    }
    if(prestuprok(y2)){
        if(mesicDnyPrestupRok[m2-1]<d2)
            return 0;
    }
    else if(!prestuprok(y2)){
        if(mesicDny[m2-1]<d2)
            return 0;
    }

    *cnt=0;
    if(y1==y2&&m1==m2){
        if(d1>13)
            return 1;
        else if(d2<13)
            return 1;
        else if(d1<=13&&d2>=13){
            if(DenvTydnu(13,i,y1,d1,m1,y1)==den){
                *cnt+=1;}
        }
        return 1;
    }

    if(y1==y2){
        if(d1>13&&d2<13){
            if(m1+1<=m2-1){
                for(i=m1+1;i<=m2-1;i++){
                    if(DenvTydnu(13,i,y1,d1,m1,y1)==den){
                        *cnt+=1;}
                }
            }
        }
        else if(d1<=13&&d2>=13){
            for(i=m1;i<=m2;i++){
                if(DenvTydnu(13,i,y1,d1,m1,y1)==den){
                    *cnt+=1;}
            }
        }
        else if(d1<=13&&d2<13){
            for(i=m1;i<=m2-1;i++){
                if(DenvTydnu(13,i,y1,d1,m1,y1)==den){
                    *cnt+=1;}
            }
        }
        else if(d1>13&&d2>=13){
            for(i=m1+1;i<=m2;i++){
                if(DenvTydnu(13,i,y1,d1,m1,y1)==den){
                    *cnt+=1;}
            }
        }
        return 1;
    }


    for(i=m1;i<=12;i++){
        if(DenvTydnu(13,i,y1,d1,m1,y1)==den){
            *cnt+=1;
        }
    }
    *cnt+=c*48000;
    for(i=y1+1+c*28000;i<=y2;i++){
        if(i!=y2){
            for(j=1;j<=12;j++){
                if(DenvTydnu(13,j,i,d1,m1,y1)==den){
                    *cnt+=1;
                }
            }
        }
        else{
            for(j=1;j<=m2;j++){
                if(j!=m2){
                    if(DenvTydnu(13,j,i,d1,m1,y1)==den){
                        *cnt+=1;

                    }
                }
                else{
                    if(d2>=13){
                        if(DenvTydnu(13,j,i,d1,m1,y1)==den){
                            *cnt+=1; }
                    }
                }
            }
        }
    }

    return 1;
}

#ifndef __PROGTEST__
int main ( int argc, char * argv [] )
{
    long long int cnt;

    assert ( CountFriday13 ( 1900,  1,  1,
                             2015,  1,  1, &cnt ) == 1
             && cnt == 197LL );
    assert ( CountFriday13 ( 1900,  1,  1,
                             2015,  2,  1, &cnt ) == 1
             && cnt == 197LL );
    assert ( CountFriday13 ( 1900,  1,  1,
                             2015,  1, 13, &cnt ) == 1
             && cnt == 197LL );
    assert ( CountFriday13 ( 1900,  1,  1,
                             2015,  2, 13, &cnt ) == 1
             && cnt == 198LL );
    assert ( CountFriday13 ( 1904,  1,  1,
                             2015,  1,  1, &cnt ) == 1
             && cnt == 189LL );
    assert ( CountFriday13 ( 1904,  1,  1,
                             2015,  2,  1, &cnt ) == 1
             && cnt == 189LL );
    assert ( CountFriday13 ( 1904,  1,  1,
                             2015,  1, 13, &cnt ) == 1
             && cnt == 189LL );
    assert ( CountFriday13 ( 1904,  1,  1,
                             2015,  2, 13, &cnt ) == 1
             && cnt == 190LL );
    assert ( CountFriday13 ( 1905,  2, 13,
                             2015,  1,  1, &cnt ) == 1
             && cnt == 187LL );
    assert ( CountFriday13 ( 1905,  2, 13,
                             2015,  2,  1, &cnt ) == 1
             && cnt == 187LL );
    assert ( CountFriday13 ( 1905,  2, 13,
                             2015,  1, 13, &cnt ) == 1
             && cnt == 187LL );
    assert ( CountFriday13 ( 1905,  2, 13,
                             2015,  2, 13, &cnt ) == 1
             && cnt == 188LL );
    assert ( CountFriday13 ( 1905,  1, 13,
                             2015,  1,  1, &cnt ) == 1
             && cnt == 188LL );
    assert ( CountFriday13 ( 1905,  1, 13,
                             2015,  2,  1, &cnt ) == 1
             && cnt == 188LL );
    assert ( CountFriday13 ( 1905,  1, 13,
                             2015,  1, 13, &cnt ) == 1
             && cnt == 188LL );
    assert ( CountFriday13 ( 1905,  1, 13,
                             2015,  2, 13, &cnt ) == 1
             && cnt == 189LL );
    assert ( CountFriday13 ( 2015, 11,  1,
                             2015, 10,  1, &cnt ) == 0 );
    assert ( CountFriday13 ( 2015, 10, 32,
                             2015, 11, 10, &cnt ) == 0 );
    assert ( CountFriday13 ( 2090,  2, 29,
                             2090,  2, 29, &cnt ) == 0 );
    assert ( CountFriday13 ( 2096,  2, 29,
                             2096,  2, 29, &cnt ) == 1
             && cnt == 0LL );
    assert ( CountFriday13 ( 2100,  2, 29,
                             2100,  2, 29, &cnt ) == 0 );
    assert ( CountFriday13 ( 2000,  2, 29,
                             2000,  2, 29, &cnt ) == 1
             && cnt == 0LL );
    return 0;
}
#endif /* __PROGTEST__ */