a,b = map(int,input().split())
l = list(input())
count = 0
for i in range(a):
  if 0<= int(l[i]) <= 9:
    count += 1
if l[a] != "-":
  print("No")
  exit()
for i in range(a+1,a+b+1):
  if 0<= int(l[i]) <= 9:
    count += 1
if count == a+b:
  print("Yes")
else:
  print("No")
  
  