#include <bits/stdc++.h>
using namespace std;
const long long N = 200010;
inline long long read() {
  long long s = 0, w = 1;
  register char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') w = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9')
    s = (s << 3) + (s << 1) + (ch ^ 48), ch = getchar();
  return s * w;
}
signed main() {
  long long a, b;
  string s;
  cin >> a >> b >> s;
  long long n = s.length();
  long long flg = 0, pp = 1;
  for (register long long i = 0; i < n; i++) {
    if (i == a && s[i] == '-') flg = 1;
    if (i != a && s[i] >= '0' && s[i] <= '9')
      pp = 1;
    else
      pp = 0;
  }
  if (pp && flg)
    puts("Yes");
  else
    puts("No");
  return 0;
}
