poj3673 水题

/*
Time:2019.12.5
Author: Goven
type：水题 
ref:
*/
#include<iostream>
#include<string>
using namespace std;

int main()
{
    string a, b;
    int la, lb, sum = 0;
    cin >> a >> b;
    la = a.length();
    lb = b.length();
    for (int i = 0; i < la; i++) {
        for (int j = 0; j < lb; j++) {
            sum += (a[i] - '0') * (b[j] - '0');
        }
    }
    cout << sum << endl;
    return 0;
}