import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int N;
    int X;
    int T;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.N = sc.nextInt();
        this.X = sc.nextInt();
        this.T = sc.nextInt();
    }
    
    //解答処理
    private long solve() {
        long answer = T;
        int takoyaki = 0;
        
        for (int i=1; takoyaki<N; i++) {
        		answer = T * i;
        		takoyaki += X;
        }
        
        return answer;
    }
    
    //出力
    public void show(long answer) {
        System.out.println(answer);
    }

} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int N;
    int X;
    int T;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.N = sc.nextInt();
        this.X = sc.nextInt();
        this.T = sc.nextInt();
    }
    
    //解答処理
    private long solve() {
        long answer = T;
        int takoyaki = 0;
        
        for (int i=1; takoyaki<N; i++) {
        		answer = T * i;
        		takoyaki += X;
        }
        
        return answer;
    }
    
    //出力
    public void show(long answer) {
        System.out.println(answer);
    }

} Main //フィールド
    Scanner sc; sc int N; N int X; X int T; T public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) Main m = new Main(sc); m new Main(sc) m.show(m.solve()) m.show m m.solve() m.solve m sc.close() sc.close sc String[] args args //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.N = sc.nextInt();
        this.X = sc.nextInt();
        this.T = sc.nextInt();
    } Main {
        this.sc = sc;
        this.N = sc.nextInt();
        this.X = sc.nextInt();
        this.T = sc.nextInt();
    } this.sc = sc this.sc this this.sc sc this.N = sc.nextInt() this.N this this.N sc.nextInt() sc.nextInt sc this.X = sc.nextInt() this.X this this.X sc.nextInt() sc.nextInt sc this.T = sc.nextInt() this.T this this.T sc.nextInt() sc.nextInt sc Scanner sc sc //解答処理
    private long solve() {
        long answer = T;
        int takoyaki = 0;
        
        for (int i=1; takoyaki<N; i++) {
        		answer = T * i;
        		takoyaki += X;
        }
        
        return answer;
    } solve {
        long answer = T;
        int takoyaki = 0;
        
        for (int i=1; takoyaki<N; i++) {
        		answer = T * i;
        		takoyaki += X;
        }
        
        return answer;
    } long answer = T; answer T int takoyaki = 0; takoyaki 0 for (int i=1; takoyaki<N; i++) {
        		answer = T * i;
        		takoyaki += X;
        } int i=1; int i=1; i 1 takoyaki<N takoyaki N i++ i++ i {
        		answer = T * i;
        		takoyaki += X;
        } {
        		answer = T * i;
        		takoyaki += X;
        } answer = T * i answer T * i T i takoyaki += X takoyaki X return answer; answer //出力
    public void show(long answer) {
        System.out.println(answer);
    } show {
        System.out.println(answer);
    } System.out.println(answer) System.out.println System.out System System.out answer long answer answer public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int N;
    int X;
    int T;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.N = sc.nextInt();
        this.X = sc.nextInt();
        this.T = sc.nextInt();
    }
    
    //解答処理
    private long solve() {
        long answer = T;
        int takoyaki = 0;
        
        for (int i=1; takoyaki<N; i++) {
        		answer = T * i;
        		takoyaki += X;
        }
        
        return answer;
    }
    
    //出力
    public void show(long answer) {
        System.out.println(answer);
    }

} public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int N;
    int X;
    int T;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.N = sc.nextInt();
        this.X = sc.nextInt();
        this.T = sc.nextInt();
    }
    
    //解答処理
    private long solve() {
        long answer = T;
        int takoyaki = 0;
        
        for (int i=1; takoyaki<N; i++) {
        		answer = T * i;
        		takoyaki += X;
        }
        
        return answer;
    }
    
    //出力
    public void show(long answer) {
        System.out.println(answer);
    }

} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        Main m = new Main(sc);
        m.show(m.solve());
        sc.close();
    }
    
	//フィールド
    Scanner sc;
    int N;
    int X;
    int T;
    
    //入力
    Main(Scanner sc) {
        this.sc = sc;
        this.N = sc.nextInt();
        this.X = sc.nextInt();
        this.T = sc.nextInt();
    }
    
    //解答処理
    private long solve() {
        long answer = T;
        int takoyaki = 0;
        
        for (int i=1; takoyaki<N; i++) {
        		answer = T * i;
        		takoyaki += X;
        }
        
        return answer;
    }
    
    //出力
    public void show(long answer) {
        System.out.println(answer);
    }

}
