CodeChef Cook79: A. Download file

note

• やるだけ。やるだけなのに問題文が難読化されてなくてすごい。
• 某合宿 day3 no2 div1

implementation

#!/usr/bin/env python3
tc = int(input())
for _ in range(tc):
    n, k = map(int, input().split())
    answer = 0
    for _ in range(n):
        t, d = map(int, input().split())
        free = min(k, t)
        k -= free
        t -= free
        answer += t * d
    print(answer)