#include <bits/stdc++.h>
int main(void) {
  int a, b, i, c = 0;
  scanf("%d%d", &a, &b);
  char s[a + b + 1];
  scanf("%s", s);
  for (i = 0; i < a + b + 1; i++) {
    if (i != 3) {
      if (s[i] >= '0' && s[i] <= '9') c++;
    } else if (s[i] == '-')
      c++;
  }
  if (c == a + b + 1)
    printf("Yes\n");
  else
    printf("No\n");
  return 0;
}
