Например:
def min2(a, b): return min(a,b) a = int(input()) b = int(input()) print(min2(a, b))
или
def min2(a, b): return min(a,b) c = int(input()) d = int(input()) print(min2(c, d))
def min2(a, b): return min(a,b) a = int(input()) b = int(input()) print(min2(a, b))
def min2(a, b): return min(a,b) c = int(input()) d = int(input()) print(min2(c, d))