function main(s) {
	a = s.split("\n")[0].split(" ").map(x => Number(x));
	s = s.split("\n")[1];
	if (s.length != a[0]+a[1]+1) {console.log("No"); return;};
	if (s[a[0]] != "-") {console.log("No"); return;};
	for (var i = 0; i < s.length; i++) {
		if (i != a[0] && s[i] === "-") {console.log("No"); return;};
	}
	console.log("Yes");
}
main(require("fs").readFileSync("/dev/stdin", "utf8"));

