NaN

N = input()

bring = []
result = 0

for i in N:
    p = int(i)
    
    if p not in bring:
        if p == 9:
            if 6 in bring:
                bring.remove(6)
                continue
        elif p == 6:
            if 9 in bring:
                bring.remove(9)
                continue
                
        for j in range(10):
            bring.append(j)
        result += 1
        bring.remove(p)
        
    else:
        bring.remove(p)
        
print(result)

N = int(input())
n_vote = []

for i in range(N):
    n_vote.append(int(input()))
    
cand = n_vote[1:len(n_vote)]
dasom = n_vote[0]
    
if(N == 1):
    print(0)

else:
    num = 0
    cand = sorted(cand, reverse = True)
    while(cand[0] >= dasom):
        dasom += 1
        cand[0] -= 1
        num += 1
        cand = sorted(cand, reverse = True)

    print(num)