22 lines
312 B
Python
22 lines
312 B
Python
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import io
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import sys
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sys.stdin = io.StringIO('''3 6
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10 5
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9 2
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8 1
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''') # 47
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import math
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n, m = map(int, input().split())
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nums = []
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for i in range(n):
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a, b = map(int, input().split())
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for j in range(math.ceil(a / b)):
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nums.append(a)
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a -= b
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nums.sort(reverse=True)
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print(sum(nums[:m]))
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