CodeForces 779B Weird Rounding

#include<map>
#include<set>
#include<ctime>
#include<cmath>
#include<queue>
#include<string>
#include<vector>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<functional>
using namespace std;

char s[10000];
int k;

int main()
{
    scanf("%s%d",s,&k);
    int len=strlen(s);
    int i ,sum=0, ans=0;
    for( i=len-1;i>=0;i--)
    {
        if(s[i]==‘0‘) sum++;
        else ans++;
        if(sum==k) break;
    }
    if(i==0||sum<k) printf("%d\n",len-1);
    else printf("%d\n",ans);
    return 0;
}