#include<bits/stdc++.h>
using namespace std;
char c;int a,b,l,i;
int main(){
	scanf("%d%d",&a,&b);
	l=a+b+1;
	for(i=0;i<l;i++){
		cin>>c;
		if(i==a&&c!='-'||i!=a&&(c<'0'||c>'9')){
			printf("No\n");
			return 0;
		}
	}
	printf("Yes\n");
	return 0;
}