template originalSource() =
 # {.checks: off.}
 include cplib/tmpl/citrus
 
 var n, m = input(int)
 var a = input(int, n)
 var b = input(int, n)
 var s = (0..<n).toseq.mapit(max(0, a[it] - b[it]))
 var c = (@[0] & s).cumsummed
 var ans = 0
 for i in 0..(n-m):
     ans.max = c[i+m] - c[i]
 print(ans)
 



# https://github.com/kemuniku/cplib
import macros;macro cplibRestore(s:static[string]):untyped = parseStmt(s)
cplibRestore("import base64\x0Amacro cplibUnpackSource(): untyped =\x0A    # \xE3\x82\xB3\xE3\x83\xB3\xE3\x83\x91\xE3\x82\xA4\xE3\x83\xAB\xE6\x99\x82\xE3\x81\xAB\xE5\xB1\x95\xE9\x96\x8B\xE6\xB8\x88\xE3\x81\xBF\xE3\x82\xB3\xE3\x83\xBC\xE3\x83\x89\xE3\x82\x92\xE5\xBE\xA9\xE5\x85\x83\xE3\x81\x99\xE3\x82\x8B\xE3\x80\x82\x0A    let z = decode(\"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\")\x0A    var s = \"\"\x0A    var i = 0\x0A    while i < z.len:\x0A        let f = ord(z[i])\x0A        inc i\x0A        for b in 0..<8:\x0A            if i >= z.len: break\x0A            if (f and (1 shl b)) == 0:\x0A                s.add(z[i])\x0A                inc i\x0A            else:\x0A                let d = ord(z[i])*256+ord(z[i+1])\x0A                let n = ord(z[i+2])+3\x0A                i += 3\x0A                for j in 0..<n: s.add(s[s.len-d])\x0A    result = parseStmt(s)\x0AcplibUnpackSource()\x0A")