/+ dub.sdl:
    name "D"
    dependency "dcomp" version=">=0.6.0"
+/
 
import std.stdio, std.algorithm, std.range, std.conv;
// import dcomp.algorithm;
// import dcomp.scanner;
// import dcomp.algorithm;
 
struct Node {
    alias NP = Node*;
    NP l, r;
    int sz;
    int v = -1, lz = -1;
    void lzdata(int x) {
        v = x; lz = x;
    }
    void push() {
        if (lz != -1) {
            l.lzdata(lz);
            r.lzdata(lz);
            lz = -1;
        }
    }
    void set(int a, int b, int x) {
        if (b <= 0 || sz <= a) return;
        if (a <= 0 && sz <= b) {
            lzdata(x);
            return;
        }
        push();
        l.set(a, b, x);
        r.set(a-sz/2, b-sz/2, x);
    }
    int get(int k) {
        if (sz == 1) {
            return v;
        }
        push();
        if (k < sz/2) {
            return l.get(k);
        } else {
            return r.get(k - sz/2);
        }
    }
    this(int sz) {
        this.sz = sz;
        if (sz == 1) return;
        l = new Node(sz/2);
        r = new Node(sz-sz/2);
    }
}
 
int main() {
    auto sc = new Scanner(stdin);
    int n; long k;
    sc.read(n, k);
    long[] a = new long[](n);
    bool[] b = new bool[](n);
    long base = 0;
    foreach (i; 0..n) {
        int f;
        sc.read(a[i], f);
        b[i] = (f == 1) ? true : false;
        if (b[i] && 2*a[i] > k) {
            writeln("-1");
            return 0;
        }
        base += 2*a[i];
        a[i] %= k;
    }
    long ba = 0;
 
    long[2][] v;
    foreach_reverse (i; 0..n) {
        a[i] *= 2; a[i] %= k;
        if (b[i]) {
            v ~= [ba, (ba+a[i])%k];
        }
        ba += a[i]; ba %= k;
    }
//    writeln(v);
    long[] di = [0];
    foreach (p; v) {
        di ~= p[0]; di ~= p[1];
    }
    di.sort!"a<b"; di = di.uniq.array;
    int m = di.length.to!int;
    auto tr = new Node(m);
    int getI(long x) {
        return binSearch!(i => di[i] >= x)(-1, di.length.to!int);
    }
    long[] dp = new long[n];
    long getD(int idx) {
        int u = tr.get(idx);
        if (u == -1) return 0;
        long a = di[idx];
        return (v[u][1]-a+k)%k + dp[u];
    }
    foreach (int i, p; v) {
        int u = tr.get(getI(p[1]));
        dp[i] = getD(getI(p[1]));
        int l = getI(p[0]);
        int r = getI(p[1]);
        if (l < r) {
            tr.set(l+1, r, i);
        } else {
            tr.set(l+1, m, i);
            tr.set(0, r, i);
        }
    }
    writeln(base + iota(m).map!getD.minimum);
    return 0;
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/scanner.d */
// module dcomp.scanner;
 
class Scanner {
    import std.stdio : File;
    import std.conv : to;
    import std.range : front, popFront, array, ElementType;
    import std.array : split;
    import std.traits : isSomeChar, isStaticArray, isArray; 
    import std.algorithm : map;
    File f;
    this(File f) {
        this.f = f;
    }
    char[512] lineBuf;
    char[] line;
    private bool succ() {
        import std.range.primitives : empty, front, popFront;
        import std.ascii : isWhite;
        while (true) {
            while (!line.empty && line.front.isWhite) {
                line.popFront;
            }
            if (!line.empty) break;
            if (f.eof) return false;
            line = lineBuf[];
            f.readln(line);
        }
        return true;
    }
 
    private bool readSingle(T)(ref T x) {
        import std.algorithm : findSplitBefore;
        import std.string : strip;
        import std.conv : parse;
        if (!succ()) return false;
        static if (isArray!T) {
            alias E = ElementType!T;
            static if (isSomeChar!E) {
                //string or char[10] etc
                //todo optimize
                auto r = line.findSplitBefore(" ");
                x = r[0].strip.dup;
                line = r[1];
            } else {
                auto buf = line.split.map!(to!E).array;
                static if (isStaticArray!T) {
                    //static
                    assert(buf.length == T.length);
                }
                x = buf;
                line.length = 0;
            }
        } else {
            x = line.parse!T;
        }
        return true;
    }
    int read(T, Args...)(ref T x, auto ref Args args) {
        if (!readSingle(x)) return 0;
        static if (args.length == 0) {
            return 1;
        } else {
            return 1 + read(args);
        }
    }
}
 
 
 
unittest {
    import std.path : buildPath;
    import std.file : tempDir;
    import std.algorithm : equal;
    import std.stdio : File;
    string fileName = buildPath(tempDir, "kyuridenanmaida.txt");
    auto fout = File(fileName, "w");
    fout.writeln("1 2 3");
    fout.writeln("ab cde");
    fout.writeln("1.0 1.0 2.0");
    fout.close;
    Scanner sc = new Scanner(File(fileName, "r"));
    int a;
    int[2] b;
    char[2] c;
    string d;
    double e;
    double[] f;
    sc.read(a, b, c, d, e, f);
    assert(a == 1);
    assert(equal(b[], [2, 3]));
    assert(equal(c[], "ab"));
    assert(equal(d, "cde"));
    assert(e == 1.0);
    assert(equal(f, [1.0, 2.0]));
}
 
unittest {
    import std.path : buildPath;
    import std.file : tempDir;
    import std.algorithm : equal;
    import std.stdio : File, writeln;
    import std.datetime;
    string fileName = buildPath(tempDir, "kyuridenanmaida.txt");
    auto fout = File(fileName, "w");
    foreach (i; 0..1_000_000) {
        fout.writeln(3*i, " ", 3*i+1, " ", 3*i+2);
    }
    fout.close;
    writeln("Scanner Speed Test(3*1,000,000 int)");
    StopWatch sw;
    sw.start;
    Scanner sc = new Scanner(File(fileName, "r"));
    foreach (i; 0..500_000) {
        int a, b, c;
        sc.read(a, b, c);
        assert(a == 3*i);
        assert(b == 3*i+1);
        assert(c == 3*i+2);
    }
    foreach (i; 500_000..700_000) {
        int[3] d;
        sc.read(d);
        int a = d[0], b = d[1], c = d[2];
        assert(a == 3*i);
        assert(b == 3*i+1);
        assert(c == 3*i+2);
    }
    foreach (i; 700_000..1_000_000) {
        int[] d;
        sc.read(d);
        assert(d.length == 3);
        int a = d[0], b = d[1], c = d[2];
        assert(a == 3*i);
        assert(b == 3*i+1);
        assert(c == 3*i+2);
    }
    writeln(sw.peek.msecs, "ms");
}
/* IMPORT /home/yosupo/Program/dcomp/source/dcomp/algorithm.d */
// module dcomp.algorithm;
 
import std.range.primitives;
import std.traits : isFloatingPoint, isIntegral;
 
//[0,0,0,...,1,1,1]で、初めて1となる場所を探す。pred(l) == 0, pred(r) == 1と仮定
T binSearch(alias pred, T)(T l, T r) if (isIntegral!T) {
    while (r-l > 1) {
        T md = (l+r)/2;
        if (!pred(md)) l = md;
        else r = md;
    }
    return r;
}
 
T binSearch(alias pred, T)(T l, T r, int cnt = 60) if (isFloatingPoint!T) {
    foreach (i; 0..cnt) {
        T md = (l+r)/2;
        if (!pred(md)) l = md;
        else r = md;
    }
    return r;
}
 
Rotator!Range rotator(Range)(Range r) {
    return Rotator!Range(r);
}
 
struct Rotator(Range)
if (isForwardRange!Range && hasLength!Range) {
    size_t cnt;
    Range start, now;
    this(Range r) {
        cnt = 0;
        start = r.save;
        now = r.save;
    }
    this(this) {
        start = start.save;
        now = now.save;
    }
    @property bool empty() {
        return now.empty;
    }
    @property auto front() {
        assert(!now.empty);
        import std.range : take, chain;
        return chain(now, start.take(cnt));
    }
    @property Rotator!Range save() {
        return this;
    }
    void popFront() {
        cnt++;
        now.popFront;
    }
}
 
 
E minimum(alias pred = "a < b", Range, E = ElementType!Range)(Range range, E seed)
if (isInputRange!Range && !isInfinite!Range) {
    import std.algorithm, std.functional;
    return reduce!((a, b) => binaryFun!pred(a, b) ? a : b)(seed, range);
}
 
ElementType!Range minimum(alias pred = "a < b", Range)(Range range) {
    assert(!range.empty, "range must not empty");
    auto e = range.front; range.popFront;
    return minimum!pred(range, e);
}
 
E maximum(alias pred = "a < b", Range, E = ElementType!Range)(Range range, E seed)
if (isInputRange!Range && !isInfinite!Range) {
    import std.algorithm, std.functional;
    return reduce!((a, b) => binaryFun!pred(a, b) ? b : a)(seed, range);
}
 
ElementType!Range maximum(alias pred = "a < b", Range)(Range range) {
    assert(!range.empty, "range must not empty");
    auto e = range.front; range.popFront;
    return maximum!pred(range, e);
}
 
unittest {
    assert(minimum([2, 1, 3]) == 1);
    assert(minimum!"a > b"([2, 1, 3]) == 3);
    assert(minimum([2, 1, 3], -1) == -1);
    assert(minimum!"a > b"([2, 1, 3], 100) == 100);
 
    assert(maximum([2, 1, 3]) == 3);
    assert(maximum!"a > b"([2, 1, 3]) == 1);
    assert(maximum([2, 1, 3], 100) == 100);
    assert(maximum!"a > b"([2, 1, 3], -1) == -1);
}
 
bool[ElementType!Range] toMap(Range)(Range r) {
    import std.algorithm : each;
    bool[ElementType!Range] res;
    r.each!(a => res[a] = true);
    return res;
}

Measured memory_bytes: 12796