import java.util.*;
import java.io.*;
import java.math.*;

class Main{

    // 0になったら終了？

    void solve(){
        long l = nl() , r = nl() , C = nl();
        long min = Lnf;
        for(long i = l ; i <= r ; i ++ ) {
            long over = (i * C / 1000) + 1;
            min = Math.min(min,(1000 * over - C * i)%1000);
            if(min == 0) break;
        }
        output.print(min);
    }   

    // for(int i = 0 ; i < n ; i ++ ) {
    //     output.print(" ");
    // }

    // for(int i = 0 ; i < H ; i ++ ) {
    //     for(int j = 0 ; j < W ; j ++ ) {
    //         output.print(" ");
    //     }
    //     output.println();
    // }
    
    /* 以下、ライブラリ等 */

    private static PrintWriter output;
    private static FastScanner fs ;
    private static Scanner sc;
    private static final int Inf  = 1000000000;
    private static final long Lnf = 1000000000000000000L;
    private static final String yes = "Yes";
    private static final String no  = "No";
    //private static final long MOD = 1000000007;
    //private static final long MOD = 998244353 ;

    private static int ni()    { return fs.nextInt(); }
    private static long nl()   { return fs.nextLong(); }
    private static double nd() { return fs.nextDouble(); }
    private static String ns() { return fs.next(); }
    private static char   nc() { return fs.next().charAt(0); }
    private static BigInteger bi() { return sc.nextBigInteger(); }
    private static BigDecimal bd() { return sc.nextBigDecimal(); }
    private static String cut(String S , int begin, int end) { return S.substring(begin,end); }
    private static char cut(String S , int idx) { return S.charAt(idx); }
    private static String tos(int val) { return Integer.toString(val); }
    private static String tos(long val) { return Long.toString(val); }
    private static int toi(String S) { return Integer.parseInt(S); }
    private static long tol(String S) { return Long.parseLong(S); }
    private static int min(int a , int b) { return (int)Math.min(a,b); }
    private static long min(long a , long b) { return (long)Math.min(a,b); }
    private static int max(int a , int b) { return (int)Math.max(a,b); }
    private static long max(long a , long b) { return (long)Math.max(a,b); }
    private static int abs(int a , int b) { return (int)Math.abs(a-b); }
    private static long abs(long a , long b) { return (long)Math.abs(a-b); }
    private static String t_n(int n , int m) { return Integer.toString(n,m); }
    private static int n_t(String n , int m) { return Integer.parseInt(n,m); }

//       i⌒i
// 　　　 |　|(ﾟ)(ﾟ)
// 　　　 |　|彡　と
// 　　 　| |＿ﾉ　 ー､
// 　　　（ミ)、　!ﾌ　/
// 　　　￠＼二二二__ノ
// 　　　　　　|　　/
// 　　　 　／ ソ⌒ 、ヽ
// 　　　　(　< 　　ヽ　）
// 　　　  ⊂＿）　　（＿つ

    private static int [] IntArray(int size) { 
        final int [] array = new int [size];
        for(int i = 0 ; i < size ; i ++ ) {
            array[i] = ni();
        }
        return array;
    }   
    private static long [] LongArray(int size) { 
        long [] array = new long [size];
        for(int i = 0 ; i < size ; i ++ ) {
            array[i] = nl();
        }
        return array;
    }   
    private static double [] DoubleArray(int size) { 
        double [] array = new double [size];
        for(int i = 0 ; i < size ; i ++ ) {
            array[i] = nd();
        }
        return array;
    }   
    private static String [] StringArray(int size) { 
        String [] array = new String [size];
        for(int i = 0 ; i < size ; i ++ ) {
            array[i] = ns();
        }
        return array;
    }
    private static char [] CharArray(int size) { 
        char [] array = ns().toCharArray();
        return array;
    }
    private static int [][] IntArray(int sizeI , int sizeJ) {
        int [][] array = new int [sizeI][sizeJ];
        for(int i = 0 ; i < sizeI ; i ++ ) for(int j = 0 ; j < sizeJ ; j ++ ) {
            array[i][j] = ni();
        }
        return array;
    }
    private static long [][] LongArray(int sizeI , int sizeJ) {
        long [][] array = new long [sizeI][sizeJ];
        for(int i = 0 ; i < sizeI ; i ++ ) for(int j = 0 ; j < sizeJ ; j ++ ) {
            array[i][j] = nl();
        }
        return array;
    }      
    private static double [][] DoubleArray(int sizeI , int sizeJ) {
        double [][] array = new double [sizeI][sizeJ];
        for(int i = 0 ; i < sizeI ; i ++ ) for(int j = 0 ; j < sizeJ ; j ++ ) {
            array[i][j] = nd();
        }
        return array;
    }   
    private static String [][] StringArray(int sizeI , int sizeJ) {
        String [][] array = new String [sizeI][sizeJ];
        for(int i = 0 ; i < sizeI ; i ++ ) for(int j = 0 ; j < sizeJ ; j ++ ) {
            array[i][j] = ns();
        }
        return array;
    }   
    private static char [][] CharArray(int sizeI , int sizeJ) {
        char [][] array = new char [sizeI][sizeJ];
        for(int i = 0 ; i < sizeI ; i ++ ) {
            array[i] = ns().toCharArray();
        }
        return array;
    }
    
    public static void main(String[] args){
        output = new PrintWriter(System.out);
        fs  = new FastScanner();
        sc  = new Scanner(System.in);
        new Main().solve();
        output.flush();
    }

    //////////////////
    // My Library //
    //////////////////

    private static int upper_bound(Integer [] array , int key) {
        return ~Arrays.binarySearch(array, key, (x,y)->x.compareTo(y)>0?1:-1);
    }
    
    private static int lower_bound(Integer [] array , int key) {
        return ~Arrays.binarySearch(array, key, (x,y)->x.compareTo(y)>=0?1:-1);
    }

}

/* 順列生成 */
class Permutation {
    ArrayList<int []> perm_list ;
    private int [] perm ;
    private int [] tmp  ;
    private int [] used ;
    private int size = 0;
    private int len  = 1;
    private int cur = 0;
    public Permutation(int [] base) {
        this.perm_list = new ArrayList<int []>();
        this.perm = new int[base.length];
        this.tmp  = new int[base.length];
        this.used = new int[base.length];
        len  = 1;
        size = base.length;
        System.arraycopy(base, 0, perm, 0, size);
        for(int i = base.length ; i > 0 ; i -- ) len *= i;
        for(int i = 0 ; i < len ; i ++ ) perm_list.add(new int[base.length]);
    }   

    public void next_permutation(int idx){
        if(idx == size) {
            for(int i = 0 ; i < size ; i ++ ) {
                perm_list.get(cur)[i] = tmp[i];
            }
            cur++;
            return;
        }
        for(int i=0;i<size;i++) {
            if(used[i] == 1) continue;
            used[i] = 1;
            tmp[idx] = perm[i];
            next_permutation(idx+1);
            used[i] = 0;
        }
    }
}
/* 素集合データ構造 */
class DSU {
    int [] parent;
    private int[] rank;
    int [] size;
    int [] vertex ;
    int [] edge ;
    public DSU(int n) {
        this.parent = new int[n];
        this.rank = new int[n];
        this.size = new int[n];
        this.vertex = new int[n];
        this.edge   = new int[n];
        for (int i = 0; i < n; i++) {
            parent[i] = i;
            rank[i] = 0;
            size[i] = 1;
        }
    }
    // 連結成分の個数
    public int groups() {
        int count = 0;
        for(int i=0;i<parent.length;i++) {
            if(i == find(i)) count++;
        }
        return count;
    }
    // 各連結成分の頂点数
    public void vertexes(int n) {
        for(int i = 0 ; i < n ; i ++ ){
            vertex[find(i)]++;
        }
    }
    // 各連結成分の辺数
    public void edges(int m , int [] from) {
        for(int i = 0 ; i < m ; i ++ ) {
            edge[find(from[i])]++;
        }
    }
    public int size(int x){
        return size[find(x)];
    }
    public int find(int x) {
        if (x == parent[x]) {
            return x;
        } else {
            parent[x] = find(parent[x]);
            return parent[x];
        }
    }
    public boolean same(int x, int y) {
        return find(x) == find(y);
    }
    /*
     *  yRoot -> parent
     */
    public void unite(int x, int y) {
        int xRoot = find(x);
        int yRoot = find(y);

        if (xRoot == yRoot) {
            return;
        }
        if (rank[xRoot] > rank[yRoot]) {
            parent[yRoot] = xRoot;
        } else if (rank[xRoot] < rank[yRoot]) {
            parent[xRoot] = yRoot;
        } else {
            parent[xRoot] = yRoot;
            rank[xRoot]++;
            size[yRoot] += size[xRoot];
        }
    }
}

/* 強連結成分分解 */
class SCC {
    private boolean [] check ;
    private List<ArrayList<Integer>> edge ;
    private List<ArrayList<Integer>> revEdge ;
    private int count ;
    private int [] vr ;
    int [] group ;
    /*
     * group[i] = 0 -> 強連結成分であるが親でない。
     * group[i] = 1 -> 強連結成分でない
     * group[i] > 1 -> 強連結成分内の頂点数を表し、iが親である。
     */
    private int groupNum ;
    /*
     * 連結成分数 (頂点数1も含む)
     */
    public SCC(int n) {
        this.check = new boolean[n];
        this.edge = new ArrayList<>();
        this.revEdge = new ArrayList<>();
        this.count = 0 ; 
        this.vr = new int[n];
        this.group = new int[n];
        this.groupNum = 0 ; 
        for(int i = 0 ; i < n ; i ++ ) {
            edge.add(new ArrayList<>());
            revEdge.add(new ArrayList<>());
        }
    }
    public void addEdge(int a , int b) {
        edge.get(a).add(b);
        revEdge.get(b).add(a);
    }
    public int getGroups(){
        return this.groupNum;
    }
    public void start() {
        int n = group.length;
        for(int i = 0 ; i < n ; i ++ ) {
            if(!check[i]) {
                First(i);
            }
        }
        Arrays.fill(check,false);
        for(int i = n - 1 ; i >= 0 ; i -- ) {
            if(!check[vr[i]]) {
                Second(vr[i], groupNum++);
            }
        } 
    }
    public void First(int now) {
        check[now] = true;
        for(int i : edge.get(now)) {
            if(!check[i]) {
                First(i);
            }
        }
        vr[count++] = now;
    }
    public void Second(int now,int groupNum) {
        check[now] = true;
        group[groupNum]++;
        for(int i : revEdge.get(now)) {
            if(!check[i]) {
                Second(i, groupNum);
            }
        }
    }
}

class FastScanner {
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
    private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
    public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
    public String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }
    public long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    public int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    public double nextDouble() { return Double.parseDouble(next());}
}