#include<bits/stdc++.h>
using namespace std;
string s1,s2;
int res=0;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
// freopen("soluong.inp","r",stdin);
// freopen("soluong.out","w",stdout);
cin>>s1>>s2;
for(int i=0;i<=s1.length();i++){
if(int(s1[i])==int(s2[i])){
res++;
}
}
cout<<res<<"\n";
}
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