#include <bits/stdc++.h>
using namespace std;
int main() {
int c=0;
string s,a;
cin >> s >> a;
int n = s.size();
int t = a.size();
for(int i=n-1,j=t-1;i>=0,j>=0;i--,j--)
{
if(s[i]==a[j])
{
c++;
}
}
cout << (n+t-2*c) << endl;
return 0;
}
I2luY2x1ZGUgPGJpdHMvc3RkYysrLmg+CnVzaW5nIG5hbWVzcGFjZSBzdGQ7CgppbnQgbWFpbigpIHsKCWludCBjPTA7CglzdHJpbmcgcyxhOwoJY2luID4+IHMgPj4gYTsKCWludCBuID0gcy5zaXplKCk7CglpbnQgdCA9IGEuc2l6ZSgpOwoKCQlmb3IoaW50IGk9bi0xLGo9dC0xO2k+PTAsaj49MDtpLS0sai0tKQoJCXsKCQkJaWYoc1tpXT09YVtqXSkKCQkJewoJCQkJYysrOwoJCQl9CgkJfQoJCgkJY291dCA8PCAobit0LTIqYykgPDwgZW5kbDsKCQoJCglyZXR1cm4gMDsKfQ==