#include <bits/stdc++.h>
const int TRUE = 1;
const int FALSE = 0;
int main() {
  int a, b;
  scanf("%d%d", &a, &b);
  char s[11];
  scanf("%s", s);
  int ans = TRUE;
  for (int i = 0; i < a; i++) {
    if (s[i] >= '0' && s[i] <= '9') {
      continue;
    } else {
      ans = FALSE;
    }
  }
  if (s[a] != '-') {
    ans = FALSE;
  }
  for (int i = a + 1; i < b; i++) {
    if (s[i] >= '0' && s[i] <= '9') {
      continue;
    } else {
      ans = FALSE;
    }
  }
  printf("%s\n", ans ? "Yes" : "No");
}
