#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int a, b, check = 0;
  cin >> a >> b;
  string s;
  cin >> s;
  for (int i = 0; i < (a + b + 1); i++) {
    if (i != a && s[i] == '-') ++check;
  }
  if (check == 0)
    cout << "Yes";
  else
    cout << "No";
}
