diff --git a/src/days/day12.zig b/src/days/day12.zig
index d940d18..26d586b 100644
--- a/src/days/day12.zig
+++ b/src/days/day12.zig
@@ -111,13 +111,26 @@ pub fn run(allocator: std.mem.Allocator) !void {
         }
     }
 
-    for (presents.items, 0..) |present, i| {
-        std.debug.print("{d}:\n{f}\n\n", .{i, present});
-    }
+    var accumulator: usize = 0;
 
     for (regions.items) |region| {
-        std.debug.print("{f}\n", .{region});
+        var area_needed: usize = 0;
+        for (region.required_presents, 0..) |amount, i| {
+            area_needed += amount * presents.items[i].area();
+        }
+        if (area_needed < region.area()) {
+            std.debug.print("{f}\nfits\n", .{region});
+            accumulator += 1;
+        }
     }
+
+    var buffer: [8]u8 = undefined;
+    var stdout_writer = std.fs.File.stdout().writer(&buffer);
+    const stdout = &stdout_writer.interface;
+
+    try stdout.print("{d}\n", .{accumulator});
+
+    try stdout.flush();
 }
 
 const Present = struct {
@@ -147,6 +160,10 @@ const Present = struct {
         const index = (y * Width) + x;
         return self.shape.isSet(index);
     }
+
+    pub fn area(self: Self) usize {
+        return self.shape.count();
+    }
 };
 
 const Region = struct {
@@ -169,5 +186,54 @@ const Region = struct {
             }
         }
     }
+
+    pub fn createEmpty(self: Self, allocator: std.mem.Allocator) !EmptyRegion {
+        return try .init(allocator, self.width, self.height);
+    }
+
+    pub fn area(self: Self) usize {
+        return self.width * self.height;
+    }
+};
+
+const EmptyRegion = struct {
+    grid: [][]bool,
+    filled_spaces: usize,
+
+    allocator: std.mem.Allocator,
+
+    const Self = @This();
+
+    pub fn init(allocator: std.mem.Allocator, width: u8, height: u8) !Self {
+        const h = try allocator.alloc([]bool, height);
+        for (0..height) |i| {
+            const w = try allocator.alloc(u8, width);
+            @memset(w, false);
+            h[i] = w;
+        }
+        return .{
+            .grid = h,
+            .filled_spaces = 0,
+            .allocator = allocator,
+        };
+    }
+
+    pub fn deinit(self: Self) void {
+        for (self.grid) |row| {
+            self.allocator.free(row);
+        }
+        self.allocator.free(self.grid);
+    }
+
+    pub fn fits(self: Self, present: Present) bool {
+        std.debug.assert(self.grid.len > 0);
+        const size = self.grid.len * self.grid[0].len;
+        if ((size - self.filled_spaces) < present.shape.count()) {
+            return false;
+        }
+
+        // TODO: Implementation
+        return false;
+    }
 };