571 B | 571 chars
import sys
from math import sqrt, pi, sin, factorial
inp = lambda : sys.stdin.readline()[:-1].strip()
mii = lambda x = " " : [*map(int,inp().split(x))]
mfi = lambda x = " " : [*map(float,inp().split(x))]
ii = lambda : int(inp())
fi = lambda : float(inp())
p = print
def solve():
n = ii()
x = ii()
l = []
ans = 0
for i in range(n):
l = mii()
diff = abs(l[0] - l[1])
if diff > x:
a = ii()
ans += a
else:
ans += max(l)
return ans
if __name__ == "__main__":
tc = 1
for t in range(1, tc+1):
ret = solve()
p(ret)