#include<iostream>

using namespace std;

#define MAX 100

int fun(int* a,int length,int p=5)

{

int i,j,k;

int time,sum=0;

for(i=length;i>0;i--)

{

time=length-i+1;

for(j=0;j<time;j++)

{

for(k=j;k<i+j;k++)

sum=sum+a[k];

if(sum%p==0)

return i;

sum=0;

}

}

return -1;

}

void main()

{

int a[MAX];

int N,i=0;

while(cin>>N)

a[i++]=N;

cout<<fun(a,i)<<endl;

}