IIT JAM 2026 Question 45: Demand theory and elasticity

The utility function of a consumer in a two-good world is $u(x_1,x_2)=\text{minimum}\{x_1,x_2\}$, where $x_1$ and $x_2$ are quantities of goods $X_1$ and $X_2$. The market prices of $X_1$ and $X_2$ are Rupee 1 and Rupees 2 per unit. Assuming income is measured on the vertical axis, the slope of the Engel curve for $X_2$ is ________ (in integer).