import sys
a, b = map(int, raw_input().split())
s = raw_input()


if s[a] == '-' and a + b + 1 == len(s):
    for i in range(len(s)):
        asc = ord(s[i])
        if a == i:
            continue
        if asc < 48 or asc > 57:
            print "No"
            sys.exit()
    print "Yes"
else:
    print "No"