Buggy python submission (verdict: Time Limit Exceeded):
#!/usr/bin/env python
import os
import operator
import sys
from io import BytesIO, IOBase

def inar():
    return [int(k) for k in input().split()]
def main():
    n,we=map(int,input().split())
    arr=[]
    for i in range(n):
        w,v=inar()
        arr.append([w,v])
    arr.sort()
    dp=[]
# ?print(arr)
    for i in range(n+1):
        lis=[0]*(we+1)
        dp.append(lis)
    # for i in range(n+1):
    #     print(*dp[i])
    for i in range(1,n+1):
        for j in range(1,we+1):
            if arr[i-1][0]>j:
                dp[i][j]=dp[i-1][j]
            else:
                dp[i][j]=max(dp[i-1][j],arr[i-1][1]+dp[i-1][j-arr[i-1][0]])
    # for i in range(n+1):
    #     print(*dp[i])
    print(dp[n][we])








BUFSIZE = 8192

class FastIO(IOBase):
    newlines = 0

    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")

if __name__ == "__main__":
    main()

Fixed submission:
#!/usr/bin/env python
import os
import operator
import sys
from io import BytesIO, IOBase

def inar():
    return [int(k) for k in input().split()]
def main():
    n,we=map(int,input().split())
    arr=[]
    for i in range(n):
        w,v=inar()
        arr.append([w,v])
    arr.sort()
    dp=[]
# ?print(arr)
    for i in range(n+1):
        lis=[0]*(we+1)
        dp.append(lis)
    # for i in range(n+1):
    #     print(*dp[i])
    for i in range(1,n+1):
        for j in range(1,we+1):
            if arr[i-1][0]>j:
                dp[i][j]=dp[i-1][j]
            else:
                dp[i][j]=max(dp[i-1][j],arr[i-1][1]+dp[i-1][j-arr[i-1][0]])
    # for i in range(n+1):
    #     print(*dp[i])
    print(dp[n][we])








BUFSIZE = 8192

class FastIO(IOBase):
    newlines = 0

    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = "x" in file.mode or "r" not in file.mode
        self.write = self.buffer.write if self.writable else None

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b"\n") + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode("ascii"))
        self.read = lambda: self.buffer.read().decode("ascii")
        self.readline = lambda: self.buffer.readline().decode("ascii")


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
input = lambda: sys.stdin.readline().rstrip("\r\n")

if __name__ == "__main__":
    main()