stones = sorted([ int(v) for v in input().split() ])

def exchange(inlist):
    a, b, c = inlist


    if b != 0:    
        d = min( ( c - a ) // 3, b)
        a, c = a + d, c - d * 2
        d = a
        inlist = sorted([ i - a for i in [a,b,c] ])
    else:
        d = c // 5
        inlist = [0,0,(c-5*d)]

    return(inlist,d)

ans = 0
product = 1
while product != 0:
    stones, product = exchange(stones)
    ans += product
print(ans)