public static void main(String[] args){

Scanner sc = new Scanner(System.in);

String s = sc.next();

int n = sc.nextInt();

String result = convert(s, n);

System.out.println(result);

}

public static String convert(String s, int numRows) {

List<Character> list = new ArrayList<>();

int n = s.length();

Character[][] martix = new Character[numRows][n];

int row = 0;

int col = 0;

int count =0;

boolean rowflag = false; //向右移动

boolean colflag = true; //向下移动

if(numRows ==1) return s;

while( count != s.length() ) {

martix[row][col] = s.charAt(count);

count++;

if(row != numRows-1 && colflag && !rowflag) { //向下存储

row++;

}

else if(row == numRows-1 ) { // 转向向右上移动

rowflag = !rowflag;

colflag = !colflag;

row--;

col++;

}

else if(row > 0 &&row < numRows-1 && rowflag && !colflag){ //向右上移动

row--;

col++;

}

else if( row == 0 && rowflag && !colflag) {

rowflag = !rowflag; //转向向下移动

colflag = !colflag;

row++;

}

}

StringBuffer result = new StringBuffer();

for(int i = 0; i < numRows ; i++) {

for(int j =0; j < n ; j++) {

if (martix[i][j] == null) continue;

if(martix[i][j] < 'z' || martix[i][j]> 'a' || martix[i][j] < 'Z' || martix[i][j]> 'A') result.append(martix[i][j]);

}

}

String a = result.toString();

return a;

}