#include <bits/stdc++.h>
int main() {
  int a, b;
  scanf("%d %d", &a, &b);
  char s[15];
  scanf("%s", s);
  int yes = 1;
  for (int i = 0, n = a + b + 1; i < n; i++) {
    if ((i == a && s[i] >= 0 && s[i] <= 9) || (s[i] == '-' && i != a)) {
      yes = 0;
      break;
    }
  }
  if (yes)
    printf("Yes\n");
  else
    printf("No\n");
  return 0;
}
