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