FROM chiffres romains TO decimal

#include <stdio.h>
int main()
{
    char r[17];
    fgets(r, 17, stdin);
    int s=0;
    for(int i=0;i<strlen(r);i++)
    {
        if(r[i]=='I')s++;if(r[i]=='V')s+=5;if(r[i]=='X')s+=10;if(r[i]=='L')s+=50;if(r[i]=='C')s+=100;if(r[i]=='D')s+=500;if(r[i]=='M')s+=1000;
    }
    for(int i=0;i<strlen(r)-1;i++)
    {
        if(r[i]=='I'&&r[i+1]=='V')s-=2;
        if(r[i]=='I'&&r[i+1]=='X')s-=2;
        if(r[i]=='X'&&r[i+1]=='L')s-=20;
        if(r[i]=='X'&&r[i+1]=='C')s-=20;
        if(r[i]=='C'&&r[i+1]=='D')s-=200;
        if(r[i]=='C'&&r[i+1]=='M')s-=200;
    }
    printf("%d\n",s);
}