l = map(int, raw_input().split())
k = raw_input()
listed = list(k)
if (len(k) == (l[0] + l[1] + 1)) and (listed[l[0]] == "-") and ((int(listed[l[0]+1]) in range(10)) and ((int(listed[l[0]-1])) in range(10))):
    print "Yes"
else:
    print "No"
