python写得P2006赵神牛的游戏，只得10分，求高手解惑！

k,m,n=map(int,input().split())
ls=[[int(i) for i in input().split()] for i in range(m)] 
cont=0
for j in ls:
    if (k//j[0])>0 and ((k//j[0])*j[1])>=n:
        print(ls.index(j)+1)
        cont=1
if cont==0:
    print(-1)