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# sPARks PL/0 Hello World !! # 在这里键入PL/0 程序 var n, i, r, sum; procedure next; r := r * i ; begin sum := 0; r := 1; read(n); i := 1; while i <= n do begin call next; sum := sum + r; i := i+1; end; write(sum); end.

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