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