import times, strutils, sequtils, math, algorithm, tables, sets, lists, intsets import critbits, future, strformat, deques template `max=`(x,y) = x = max(x,y) template `min=`(x,y) = x = min(x,y) template `mod=`(x,y) = x = x mod y template scan2 = (scan(), scan()) template scan3 = (scan(), scan()) let read* = iterator: string {.closure.} = while true: (for s in stdin.readLine.split: yield s) proc scan(): int = read().parseInt proc scanf(): float = read().parseFloat proc toInt(c:char): int = return int(c) - int('0') proc solve():int= var p = scan() k = scan() dp = newseqwith(k+1,newseqwith(2,0)) md = 10^9+7 # N = 0のとき、次が0になる # 掛け算:0~(p-1)のp通り # 足し算:0の1通り # 次が0以外になる # 掛け算:0通り # 足し算:p-1通り # N != 0のとき、次が0になる # 掛け算:0の1通り # 足し算:1通り # 次が0以外になる # 掛け算:p-1通り # 足し算:p-1通り dp[0][0]=1 for v in 1..k: dp[v][0] = (dp[v-1][0]*(p+1) + dp[v-1][1]*2).mod(md) dp[v][1] = (dp[v-1][0]*(p-1)+dp[v-1][1]*(p-1)*2).mod(md) #echo dp.join("\n") return dp[k][0] echo solve()