minCostPerGram = (lambda x : x[0] / x[1])(list(map(int, input().split())))
for _ in range(int(input())) :
    x, y = map(int, input().split())
    minCostPerGram = min(minCostPerGram, x/y)

print(f'{round(minCostPerGram * 1000, 2):.2f}')