C++ :

#include <bits/stdc++.h>
using namespace std;

char a[50010], b[50010];

int main() {
    cin >> a >> b;
    int l1 = strlen(a), l2 = strlen(b);
    if (l1 % l2 != 0) {
        printf("No");
        return 0;
    }
    for (int i = 0; i < l1; i += l2) {
        // a从每个长度为l2的起点开始，取长度
        for (int j = 0; j < l2; ++j) {
            if (a[i + j] == b[j])
                continue;
            else {
                printf("No");
                return 0;
            }
        }
    }
    printf("Yes");
    return 0;
}