#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  bool x = 1;
  for (int i = 0; i < a + b + 1; i++) {
    if (i == a && s[i] != '-') x = 0;
    if (i < a && s[i] < '0' && s[i] > '9') x = 0;
    if (i > a && i < a + b + 1 && s[i] < '0' && s[i] > '9') x = 0;
    if (s.size() != a + b + 1) x = 0;
  }
  if (x)
    cout << "Yes";
  else
    cout << "No";
  return 0;
}
