#include<stdio.h>

int main(){
	int a,b;
	scanf("%d %d", &a,&b);
	char code[a+b+3]="";
	scanf("%s", code);
	if((code[a]=='-')&&(code[a+1]>=48)&&(code[a+1]<=57)) printf("Yes");
	else printf("No");
	return 0;
}