import sequtils, strutils
var
    ab:seq[int] = readLine(stdin).split(" ").map(parseInt)
    s:seq[char] = toSeq(readLine(stdin).items)
    i:int = 0
proc main():string =
    if not(s[ab[0]] == '-') or not(len(s) == (ab[0] + ab[1] + 1)):
        return "No"
    for c in s:
        if (c == '-') and (i == ab[0]):
            continue
        elif not(isDigit(c)):
            return "No"
        else:
            return "Yes"
        i += 1
echo main()