UVA 10394

#include<stdio.h>
int prime[2000000]={};
int ara[200000]={};
int main()
{
    int i,k=2;
    int j;
    int n=2000000;
    int cnt=0;
    for(i=0;i<n;i++) prime[i]=i;

    for(i=2;i<n;i++) {
        if(prime[i]!=0){
            ara[cnt] = prime[i];
            cnt++;
            for(j=2;j<n;j++){
                prime[j*prime[i]]=0;
                if(prime[i]*j>n) break;
            }
        }
    }

    int bla;
    printf("%d\n",cnt);
    int as=0;
    while (scanf("%d",&bla) != EOF) {
        as = 0;
        for (i=0;i<cnt;i++) {
            if((ara[i+1]-ara[i]) == 2) as++;
            if (as==bla) break;
        }
        printf("(%d, %d)\n",ara[i],ara[i+1] );
    }
    return 0;
}